Good article although I have two main disagreements.
1. Fully round and rounded rectangle elements are regularly used together in UIs. Material 3 does it plenty, which is what this is all based off of I assume.
2. Consistency between light and dark modes seems like a low priority to me. I imagine most users just pick one although I don’t have data to back me up.

The “glass” affect seems like Material 3’s “surfaces.”

And finally, they could be running some experimentation on something like the comments view. A/B test, etc.

But overall good article. Thanks!